The industrial arts contain a great many fluid systems requiring multiport valving means directly responsive to pressure changes inside the fluid containing system. And, traditionally, such valves, have been manufactured as discrete components, incorporable into any system requiring the valves by connection to the inlet(s) and outlet(s) of the valve. In short, the necessary components of the valve, namely valve face, valve seat, and valve body are parts of a fully assembled valve combination provided by the manufacturer thereof.
For many fluid systems such state of affairs is satisfactory, but thereby design constraints have been imposed upon the detailed construction of the system as a whole. For example, discrete fluid flow lines e.g., pipes, have become needed to pass fluid to and from the valve combination. To some extent the art is discouraged from constructing fluid systems wherein complex valving are disposed inside bore holes of a casting, and wherein preformed channels inside the casting constitute the (piping) connections to the valve. Substitution of a relatively inexpensive casting for a multiplicity of short lengths of pipe can offer space economy, cost savings and product quality improvement to fabricators of numerous fluid systems.
One particular instance of such a design constraint known to the inventor hereof has been in pressure swing regenerative dryer systems wherein the twin dryer towers in the system have been interconnected through reversing valves by short lengths of pipe. Formation of the interconnections as channels within a cast base, as is suggested in the dryer system described in U.S. Ser. No. 060,103 filed July 24, 1979, was made difficult by the need to build valve seats directly into the channel walls. A more facile cast tower support structure resulted when a valve assembly constructed according to practice of this invention was employed (See Ser. No. 138,158, filed concurrently herewith).
Other fluid systems that have faced comparable design constraints are systems for demineralization of water and swimming pool filtration systems.